Tilt mechanism for venetian blinds



J. J. Dl lENNO Filed Dec. 18. 1950 TILT MECHANISM FOR VENETIAN'BLINDSthe'.r operator.

Patented Oct. 21, k1952 "LUNITED STATES PATENT OFFICE v 2,614,625.V j

'IILT'VMECHANISM F OR" VENETIAN BLIDS'. `lohn J. Di IennoVPhiladelphia,Pm, assignor toi Carey-'McFall'y Company, Philadelphia,r Pan,A a.corporation of Pennsylvania AApplication December 18, 1950, Seral'No;201,288`

2 Claims.-

\ Thepresent invention relates to newvandusesociated with thetilt-lshaft and driven bythe worm wheel which in turn-isl rotated' bymeans ofa cord.` operatedf pulley. Usually the vcord passesr over the pulley andhas its two ends hanging? free. so that they-may be grasped by When.the'Venetian blind is in use, the. tilt..cord inadvertently slipsin onedirection ory the. otherover the pulley. until, after repeatedmanipulationsofzthe blind, the tiltcord -isnotcentrallylocatedon `thepulley.` Accordinglyit. becomes necessaryV periodically to relocate thetiltl cord uponthe pulley; 'Ihis may beV done by.. manually;` threadingthe tilt' cord `about' the pulley, a` difficult .andr tedious operation,or by disengaging'. the gearv fromtheworm wheel'sothat the latter-may berotatedffreely relativel tol they gear, forV example, by'eliminating.entirely a portion: of thefteeth on the-gear segment so ythatinatfileast `one position .the gear andwormare out of. mesh, aconstruction'which' mayujam when the-gearisreturned into engagement withthe Worm.

With the? foregoing `in mind,l a principal.' object of the. present.invention. is .to provide a: tilt .mechanism for Venetian blindsembodying= a novel constructionand arrangementvof. the gearandzworm'wheel to permit rotation of Vthe latter withffrespect .to .thegearwithout complete disengagement between ythem.`

Another .object ofl the present: invention .is

to provide. annovel. Venetianv .blind tiltxmech- .anism of j thestated'. character whichr isxcon- .structed-'to permit :the tilt cord'to be .easily 'positionedcentrally. with` respect vto the pulley withoutdisengagingtheworm andthe gear. .A further object i:off the presentlinvention is e to'provide a novel Venetian blind: tilt mechanism whereinthe .gear 'is displaceable'with respect to'V the worm wheel and in vat.least one positionoi the Venetian blind may be..di'splaced inforderftoallow rotation of thef-'worm wheel `with respect to the gear.

A still .further object of the present invention `is to providea .noveli Venetian blind tilt mechanism` having. the-Y. features andcharacteristics set `forth. which-- may be manufactured. easily vandcheaply andl which is entirely' eflicientand eectver in operation anduse. f

of thel operation and construction thereof-'are hereinafter more fullyset forth and described with referenceto the .accompanying drawing; inwhich: y

Fi`g`.fIv lis a fragmentary. side' elevationalwew of thetiltmechanismfora Venetianblind.

Fig. '2.is an end elevationalview of the. tilt mechanism of' the presentinvention installed in the headvcasing of a Venetianblind;

Fig. Bis as enlarged sectional view showing the position of the'gear andworm when the Venetian. blind slats are intheirhorizontal po.- sition;

Figyll is an enlargedsectional view showing the position of the gear andworm.when.the Venetian' blind slatsare in their extreme tilted position;v

' Fig. 5 isl an enlarged sectionalview illustrating vtheupwarddisplacement of the gear'with respectl to the worm wheel therebyallowingythe worm'wheelto be rotated without simultaneously rotatingthev gear;

Fig. 6 is afperspective view'of the gear elementfor the presentinvention blind tilt.mech. anism; and, o f

.Fig.-7 'is a longtudinalsectional View taken on line 1-1 Fig. 5.

Referring more specifically to the drawing, reference numeral IGdesignates generally the head casing for aA Venetian blind. The casing I0 comprises. a base portion II and relatively vertical side Wallportions I2 and I3 which terminate at their upper ends in longitudinalchannels I4 and I5 respectively. These channels Ill 'and I5, aside fromstiiening vthe head casing I0 also` serve to secure `the yvarious .com-`ponent partsl of the Venetian blindto the head casing.

In accordance .with the present invention,.,the tilt mechanismdesignated generally at I6 comprises a -cross frame'member I'i. tratedembodiment of the invention, the cross framemember I1 is rformed of aplate I8 having a foot ange liiresting on andsecured to the bottom panelII of the rhead casing ID. The plate I8 is also .provided with an upperange 2| terminating. in vertical projections. or `ears 22 andA 23.AThese vears 22'and 23extend into thelongitudinal casing channels I4andI5're- .spectivelyat ;the..11pper..edges of ;the,.front..chan,

In the illusnel I2 and rear channel I3, and impart rigidity to the headcasing.

The plate I8 has secured therein a rivet or stud 24 on which a gear 25is rotationally mounted. The stud 24 passes through an enlargedeccentric opening 26 in the gear 25 to allow the gear relativetransverse movement with respect to the plate I8 as more fully describedhereinafter. Formed as an integral part of the gear' 25 and extendingoutwardly therefrom is an axial extension 21 which terminates in an arm28 that is disposed in a plane parallel to the plane of the gear 25 andspaced axially therefrom. Aprectangular opening 29 is provided centrallyin the arm 28 and is adapted to receive a correspondingly shaped tiltshaft 30 of the Venetian blind, which in turn carries the tilt bar 3|and the Venetian blind tapes 32 and 33.

A worm wheel 35 is secured upon a shaft 36 rotatably mounted in theplate I8 as indicated at 3'I directly beneath the gear 25. Fixedlysecured tothe outwardly extending end of the shaft 35 is a notched orserrated pulley 38 about which passes the customary tilt cord or rope39. The cord 39 is directed downwardly through an opening 4I] on thebottom panel II of the head casing Iii by means of guides 4I formed asanintegral part of the lower plate flange I9.

The gear 25 is provided with a plurality of teeth 42 which are adaptedto engage the Worm 35 so that rotation of the latter by pulling the tiltcord 39 operates rto rotate the gear 25 and thereby change the angle ofdisposition of the Venetian blind- .-slats. In accordance with thepresent invention, and with reference particularly to Fig. 6, the teeth42 are arranged in substantially equal spaced relation about the gear 25except at the junction with the axial extension 21. In order to Aprovideteeth at this place and to maintain a continuity in the teeth around theentire periphery of the gear 25 openings are provided at the junction asindicated at 43. The openings 43 are so positioned that the metalbetween them is substantially the same width as that of the teeth 42 anddisposed in the same spaced relation as the teeth 42 thus effectivelyproviding teeth 44 at the junction of the gear 25 with the axialextension 2! for engagement with the Worm 35.

As previously described, the opening 26 in the gear 25 is larger thanthe diameter of the stud 24, thereby allowing relative transversemovement of the gear 25 with respect to the plate I8 and the worm 35.Also, the opening 25 is positioned eccentrically in the gear 25 so thatwhen the Venetiany blind slats are in the horizontal position whichcorresponds to the gear position illustrated ,in Fig. 3, the teeth 42 ofthe gear 25 are in full engagement with the worm 35 and the lower sideof the opening 25 bears against the stud 24. As the Venetian blind slatsare tilted by rotation of the gear 25 the teeth thereon are graduallywithdrawn from full engagement with the worm 25 due to the eccentricityof the opening 2B in the gear 25 until when the slats are in theirextreme tilted position which corresponds to the position of the gearasshown in Fig. 4 the teeth 43 on the gear 25 are only in partialengagement with the worm wheel 35. In this position the upper portion ofthe opening 25 bears against the stud 24.

When it is desired to relocate the tilt cord 39 with respect to thepulley 38, it is merely necessary to tilt the Venetian blind slats tothe proper limit position, for example as indicated at Fig. 4, and thencontinue to exert a substantial pull on the short end of the tilt cord.Since the tilt rod 3!) can not be rotated any further, continuedpressure of the worm 35 against the teeth 44 causes the gear 25 to bedisplaced upwardly with respect to the worm 35 as illustrated in Fig. 5.By this construction the teeth 44 of the gear 25 are carried upwardly bythe worm 35 and ride over the convolutionsthereof thus allowing the wormto berotated until the tilt cord 39 is properly relocated on the pulley33. From the foregoing, it will be observed that the present inventionprovides a novel Venetian blind tilt mechanism embodying a novelconstruction and arrangement of gear and worm to permit rotation of thelatter with respect to the gear without complete disengagement of thegear and Worm. Furthermore, the present invention provides a novelVenetian blind tilt mechanism which is constructed to permit the tiltcord to be easily positioned centrally with respect to the pulleywithout disengagement of the worm and gear.

While a certain embodiment of the present invention has been illustratedand described herein, it is not intended to limit the invention to suchdisclosure and changes and modifications may be incorporated andembodied therein within the scope of the following claims.

I claim:

1. In tilt mechanism fora Venetian blind having the usual tilt shaft forangularly positioning the slats of the blind, a rotatably mounted Worm,a tilt cord connected to said worm for rotationally actuating thelatter, a member including a gear portion meshed with said worm andhaving a lateral extension from a peripheral part of the gearterminating outwardly in an'arm disposed parallel tok said gear portionand to which said tilt shaft is connected so that rotation of the gearAby the worm operates normally to impart a vcorresponding rotation tothe tilt shaft, said member gear portion having teeth extendingcircumferentially thereof from one side of the said lateral extensioncontinuously to the other side thereof and said member having openingsin the junction portion of the member between the gear and lateralextension to provide gear teeth along said junction and thereby acontinuous series of teeth .entirely circumferentially of the said gearportion, and means mounting said gear for limitedv radial movementtoward and away fromv the worm inthe limit tilt positions only of theblind so that continued pullexerted on the tilt cord in said limitpositions operates to displace the gear outwardly from the worm andcause the worm to ride over the teeth ofthe gearthereby causing rotationof the worm relative to the gear to effect repositioning of the tiltcord.

2. In tilt mechanism for a Venetian blind having the usual tilt shaftvfor angularly positioning the slats of the blind, a rotatably mountedworm, a tilt cord connected to said Worm for rotationally actuating thelatter, a .member including a gear portion normally meshed with saidworm and having a lateral extension from a peripheral part of the gearterminating out- Wardly in an arm disposed parallel to said gear portionand to Which said tilt shaft is connected so that rotation of the gearby the worm operates normally to impart a corresponding rotation to thetilt shaft, said member gear portion having teeth extendingcircumferentially thereof fromone side of the said lateral extensioncontinuously tov the other s idelthereof said junctionv and thereby acontinuous .series of teeth entirely circumferentially of the said gearlportion, and means eccentrically mounting said gear so that 'in thelimit tilt positions of the blind the gear teeth mesh with the worm to alesser depth than in the other tilt positions of the blind, said meansalso mounting said gear for limited radial movement toward and away fromthe worm in the limit tilt positions. only of the blind so thatcontinued pull exerted on the tilt oord in said limit positions operatesto v displace thegear outwardly, from the Worm andglvlg; cause the wormto ride. over the: teeth ofA the 6 t. gear thereby causing rotatioiifo!the worm relative to the gear to eect repositioning of the tilt cord.

JOHN J. DI IENNO.

REFERENCES jfITED The following references are of record in the file ofthis patent:

UNITED s'rA'rEs PATENTS Number Name. Y Date 2.174.994 Nelson.; Oot.y3v.1939 2,224,712 Balthasar' Deo. 10. 1940v 2,282,272 Waltzinger May 5.19423 2.580.479.

Strogran J Jan. 1. 1952

